“…Many stochastic differential equations, such as the stochastic oscillator, have stochastic Hamiltonian formulation and an associated stochastic symplectic structure. Concerning their numerical integration, stochastic symplectic methods have received extensive attentions (see e.g., [1,2,4,3,5,8,11,17,18,19,27,25,26] and references therein), for their superiority in numerical computations compared with non-symplectic ones. The motivation of this paper is to explain the superiority of stochastic symplectic methods, by studying the LDPs of numerical methods for a linear stochastic oscillator Ẍt + X t = α Ẇt with α > 0, and W t being a 1-dimensional standard Brownian motion defined on a complete filtered probability space (Ω, F , {F t } t≥0 , P).…”